The present invention relates to battery charging control systems for vehicles which are suitable for use with generators having an auxiliary rectifier, and more particularly the invention relates to a system which is capable of alerting the driver to the occurrence of faults in the generator or the like by means of a generation indicator.
FIG. 1 shows a known battery charging control system of the above type, and connected to the output side (the "L" terminal) of an auxiliary rectifier 4 is a fault warning resistor 8 having a resistance value which is lower than those of an initial excitation resistor 6 and an indicating lamp 10. As a result, when a generation fault or the stoppage of power generation is caused due to a break failure in the excitation circuit, a current flows from a battery 11 through the lamp 10 and the resistor 8 so that the lamp 10 is turned on and the driver is alerted to the fault.
However, this construction is disadvantageous in that during the initial period of generation immediately following the closing of a key switch 9, a part of the expected initial excitation current flows to the resistor 8 instead of a field coil 2, so that the initial excitation current which must be supplied to the field coil 2 becomes insufficient somewhat, making it necessary to further decrease the resistance value of the initial excitation resistor 6 to compensate for the loss. While this has the effect of increasing the initial excitation current, it is necessary to use a resistor of a greater power capacity for the initial excitation resistor 6 with the resulting further increase in the size of the resistor 6 and the cost. It is also necessary to use a resistor of a considerably large power capacity for the warning resistor 8 itself.